Pump for liquids

ABSTRACT

The pump includes a body having two inlets, arranged one above the other, and an outlet. A pair of spaced-apart impellers rotate within the body between the two inlets and draw liquid into the body through the two inlets, respectively, and discharge the liquid through the outlet. Surface liquid flows over an annular float into the upper inlet. The body is formed of two telescoping parts adjustable so that one of the inlets may be closed. Top and bottom walls within the body define an impeller chamber, and the upper impeller is located closer to the top wall than the spacing between the lower impeller and the bottom wall, so that the upper impeller develops a higher pressure than the lower impeller.

United States Patent [72] lnventor Walter J. Otto Wantagh, N.Y.

[21] Appl. No. 852,252

[22] Filed Aug. 22, 1969 [45] Patented Oct. 5, 1971 [73] Assignee JuliusL. Englesberg Rockville Centre, N.Y.

54 PUMP FOR LIQUIDS 7 Claims, 2 Drawing Figs.

[52] US. Cl 210/121, 210/169, 210/416,415/l00 [51] Int. Cl ..B0ld 35/26,BOld 35/02 [50] Field of Search 417/424;415/100,131,88;210/l2l,416,167,169, 172, 152, 251

[56] References Cited UNITED STATES PATENTS 2,106,600 1/1938 Hepler415/100 X Primary ExaminerF rank A. Spear, Jr. Att0rneyBreitenfeld &Levine ABSTRACT: The pump includes a body having two inlets, arrangedone above the other, and an outlet. A pair of spacedapart impellersrotate within the body between the two inlets and draw liquid into thebody through the two inlets, respectively, and discharge the liquidthrough the outlet. Surface liquid flows over an annular float into theupper inlet. The body is formed of two telescoping parts adjustable sothat one of the inlets may be closed. Top and bottom walls within thebody define an impeller chamber, and the upper impeller is locatedcloser to the top wall than the spacing between the lower impeller andthe bottom wall, so that the upper impeller develops a higher pressurethan the lower impellerv PUMP FOR LIQUIDS The invention relates tocentrifugal pumps, and more particularly to such a pump including twoimpellers on a single shaft for simultaneously moving liquid in twodifferent directions through the pump body.

It is an object of this invention to provide a pump capable, whenimmersed in a body of liquid, of simultaneously (a) pumping liquid frombelow the liquid surface, and (b) skimming liquid from the surface ofthe body. Advantageously, the pump is associated with a filter so thatmatter suspended in the liquid body as well as floating particles can befiltered out.

It is another object of the invention to provide such a pump which canbe adjusted to pump only liquid from below the surface.

It is a further object of the invention to provide such a pump in whichno seal is required around the shaft which carries the two impellers.

It is an additional object of the invention to provide a compact pump,,skimmer and filter unit which can be accommodated within the small spaceallocated in industrial electroplating vessels.

Additional objects and features of the invention will be apparent fromthe following description in which reference is made to the accompanyingdrawings.

In the drawings:

FIG. 1 is a vertical cross-sectional view through a pump and filterarrangement according to the present invention, the pump being adjustedfor pumping liquid both on and below the surface; and

FIG. 2 is a vertical cross-sectional view of a portion of the pumpadjusted to pump only liquid below the surface.

The pump chosen to illustrate the present invention includes a lowerpump body section and an upper pump body section 11 telescopicallyarranged within the lower section 10. Two O-ring seals 9 surroundsection 1 1, only one of these seals being in use in the FIG. 1position. The upper body section 11 is formed at its upper end with aflange 12 upon which an electric motor 13, for driving the pump, isseated. In the adjusted position shown in FIG. 1, the flange 12 rests ona positioning ring 14 which in turn rests on a support plate 15, thesection 11 passing through an opening in the plate. The plate 15 isadapted to be mounted on the vessel (not shown) containing the liquid tobe pumped and filtered, in such a way that the pump body 10, 11 ispartially immersed below the liquid surface 116. The pump body and motorare fixed to the plate 15 by screws 17 (one shown in FIG. 1) passingthrough holes in plate 15, ring 14, and flange 12, and threaded into thebase of motor 13.

Within lower pump body section 10 is an impeller cavity 20 defined atits lower end by the bottom wall 21 of section 10, and at its upper endby the bottom wall 22 of section 11. The pump body is furnished with twoinlets, the lower inlet 23 being in the center of wall 21. Inlet 23 isshown carrying an adapter 24 for connection to a hose (not shown). Thehose is used when it is desired to mount the pump outside theliquidcontaining vessel, in which case the free end of the hose isplaced in the liquid. The upper inlet comprises apertures 25 in thesidewall of upper body section 11, the apertures being spaced above thebottom wall 22. In the position of FIG. 1, the inlet apertures 25 areoutside the lower body section 10. Adjacent to bottom wall 21, thesidewall of body section 10 is formed with an outlet 26.

Fixed to the motor shaft 29 is the upper end of an impeller shaft 30,the lower end of which passes through an opening 31 in the wall 22 andinto the impeller cavity 20. Within the cavity 26 are two impellers 32and 33, which may be identical, both fixed to the impeller shaft 30.Impeller 32, at the lower end of shaft 30, is arranged when rotated todraw liquid in through inlet 23 and deliver it to outlet 26. Impeller33, spaced above impeller 32, has a reverse orientation with respect tothe latter impeller, and hence draws liquid in through inlet 25, viaopening 31. Upper impeller 33 is spaced closer to top wall 22 oftheimpeller cavity 20 than the spacing between lower impeller 32 and thebottom wall 21. Consequently, impeller 33 develops a higher pressurethan impeller 32, and the liquid drawn through inlet 25 by impeller 33is forced through outlet 26 together with the flow from inlet 23.

An annular float 36 having a depending skirt 37 surrounds the region ofthe pump body having the inlet apertures 25. The internal diameter ofthe float is only slightly larger than the external diameter of bodysection 10, so that the float is free to move longitudinally withrespect to the pump body. In practice, the inlet apertures 25 arelocated below the liquid surface 16, but the float 36 insures that thebulk of the liquid entering apertures 25 flows over the top of thefloat, i.e., the float 36 serves as a skimmer. Furthermore, since thefloat is free to move vertically with respect to the pump body, itcontinues to serve its skimming function regardless of minor variationsin the liquid level.

In the present illustration, outlet 26 is connected by a short length oftubing 38 to the inlet 39 of a filter chamber 40. The filter chamber issupported by plate 15. Within the chamber 40, a filter tube 41 rests onan annular ridge 42 projecting from the chamber bottom wall 43. Asimilar ridge 44 presented by the chamber cover 45 presses against theupper end of the filter tube 41. The cover 45 and chamber 40 are lockedtogether by a stem 46, the lower end of which is threaded into thebottom wall 43, and the threaded upper end of which carries aninternally threaded knob 48. Cover 45 is formed with an outlet 47 whichmay communicate, by means of suitable tubing (not shown), with theliquid-carrying vessel, so that filtered liquid is returned to thevessel. It will be noted that inlet 39 communicates with the annularspace surrounding filter tube 41, and outlet 47 communicates with theannuiar space within the filter tube. Thus, liquid is forced to flowthrough the filter tube before leaving chamber 40.

In operation, rotation of impeller shaft 30 by motor 13 causes rotationof impellers 32 and 33 within cavity 20. Impeller 32 draws liquid,including undesirable particles suspended in the liquid, through inlet23 and discharges it through outlet 26. At the same time, due to theaction of impeller 33, liquid and floating particles are skimmed off thesur face of the liquid. The surface liquid flows over the top of float36, through inlet apertures 25, opening 31, and chamber 20 to outlet 26.The mixture of surface liquid, floating particles, below surface liquid,and suspended particles leaving outlet 26 flows through filter chamber40, during which flow the particles are caught by filter tube 41. As aresult, only filtered liquid leaves chamber 40 through outlet 47. Itshould be mentioned that since impeller 33 operates to drive liquiddownwardly, no seal is needed between the impeller shaft 30 and the pumpbody, since the action of impeller 33 prevents flow of liquid up theshaft.

The pump of the present invention is so conceived that it may beadjusted, when desired, to pump below-surface liquid without skimmingthe surface of the liquid. The pump body is shown in FIG. 2 after suchan adjustment. The adjustment is made by removing screws 17 andwithdrawing positioning ring 14 from beneath flange 12. If the ring ismade in two halves, they are simply withdrawn laterally. If the ring iswhole, the assembly of motor 13 and body section 11 is lifted upwardly,bring impellers 32 and 33 with it, and ring 14 is simply slippeddownwardly past the impellers for removal. The body section 11 is thenreplaced, as shown in FIG. 2. Since body section 10 remains in the samelocation it occupies in FIG. 1, removal of ring 14 causes the bodysection 11 to move further into section 10 before flange 12 comes torest on support plate 15, whereupon screws 17 once again secure section11 and motor 13 to the plate. Inlet apertures 25 are now located withinsection 10, with seals 9 on both sides of it, so that these apertureswill not longer function as inlets to the pump body. Of course, theannular float 36 is also not used, since no skimming is to be performed.

In the arrangement of FIG. 2, impeller 32 serves the same purpose as itdoes in the FIG. I arrangement. In addition,

although impeller 33 no longer serves to skim the liquid surface, it isnot without function. Some liquid flows around the peripheral edge ofimpeller 32 and into the space between the impellers. Ordinarily thisliquid would tend to travel up rotating shaft 30, and hence a seal wouldbe provided around the shaft, perhaps between the shaft and the sidewallof opening 31. However, due to the presence of impeller 33, which asmentioned above develops a higher pressure than impeller 32, no suchseal is needed, since impeller 33 constantly urges the liquid whichfills the cavity 20 downwardly, so that no liquid ever reaches theopening 31.

The spacing between impellers 32 and 33 is also important, since itallows a column of liquid to exist between the impellers. Impeller 33,during its rotation, tends to suck air into the pump body, and if theblades of impeller 33 were simply mounted on the upper face of impeller32, or if impellers 32 and 33 were arranged back to back, this air mightbe forced past the edge of impeller 32 and into outlet 26, especiallysince impeller 33 develops a higher pressure than impeller 32. However,the column of liquid between the impellers, within cavity 20, serves asa trap to prevent air from reaching impeller 32.

The invention has been shown and described in preferred form only, andby way of example, and it is understood, therefore, that many variationsmay be made in the invention which will still be comprised within itsspirit.

What is claimed is:

l. A pump for liquids comprising:

a. a pump body having upper and lower inlets arranged one above theother, and an outlet,

b. top and bottom walls within said body defining an impeller chambercommunicating with said inlets and outlet, said lower inlet being insaid bottom wall and said top wall having an opening communicating withsaid upper inlet,

c. an impeller shaft extending into said body through said opening,

means for rotating said shaft, and

e. an upper and a lower impeller fixed to and rotatable with said shaft,said impellers being located within said chamber between said twoinlets, said outlet being between said lower impeller and said bottomwall, said lower and upper impellers when rotated drawing liquid inthrough said lower and upper inlets, respectively, moving the liquid inopposite directions through said chamber, and discharging the liquidthrough said outlet,

whereby said upper impeller serves to both move liquid from said upperinlet to said outlet and prevent flow of liquid from said chamberupwardly along said shaft. 2. A pump as defined in claim 1, including afilter commu- 5 nicating with said outlet.

3. A pump as defined in claim 1, including an annular float surroundingthe portion of said pump body having the upper of said inlets, surfaceliquid flowing over said float to said upper inlet.

4. A pump as defined in claim 1, wherein said pump body is formed of twotelescoping parts, one of said inlets being formed in each of saidparts, the inner of said parts being movable into the outer of saidparts to close one of said inlets.

5. A pump as defined in claim 1, wherein the upper of said impellers isspaced closer to said top wall than the spacing between the lowerimpeller and said bottom wall.

6. A pump as defined in claim 5, wherein the upper of said inlets islocated above said top wall, said upper inlet communicating with saidchamber via said opening.

7. A pump for liquids comprising:

a. a pump body having an inlet and an outlet;

b. first and second walls within said body defining an impeller chambercommunicating with said inlet and outlet, said inlet being in said firstwall, an impeller shaft extending into said chamber through an openingin said second wall,

d. meansforrotatingsaid shaft,and e. first and second independentimpellers within said chamber and fixed to and rotatable with saidshaft, said impellers being spaced apart along the length of said shaft,said first impeller being spaced relatively far from said first wall butsaid first impeller being closer to both said inlet and outlet than saidsecond impeller and serving to draw liquid through said inlet anddischarge liquid through said outlet, said impellers being arranged sothat most of the liquid moves through only said first impeller as itflows from said inlet to said outlet and said second impeller beingspaced relatively close to said second wall and urging liquid towardsaid outlet in a direction opposite to the direction in which said firstimpeller moves liquid, thereby preventing any liquid from moving throughsaid opening from said chamber,

the space between said impellers being filled with liquid which servesto prevent air, entering said chamber through said opening, fromreaching said outlet.

1. A pump for liquids comprising: a. a pump body having upper and lowerinlets arranged one above the other, and an outlet, b. top and bottomwalls within said body defining an impeller chamber communicating withsaid inlets and outlet, said lower inlet being in said bottom wall andsaid top wall having an opening communicating with said upper inlet, c.an impeller shaft extending into said body through said opening, d.means for rotating said shaft, and e. an upper and a lower impellerfixed to and rotatable with said shaft, said impellers being locatedwithin said chamber between said two inlets, said outlet being betweensaid lower impeller and said bottom wall, said lower and upper impellerswhen rotated drawing liquid in through said lower and upper inlets,respectively, moving the liquid in opposite directions through saidchamber, and discharging thE liquid through said outlet, whereby saidupper impeller serves to both move liquid from said upper inlet to saidoutlet and prevent flow of liquid from said chamber upwardly along saidshaft.
 2. A pump as defined in claim 1, including a filter communicatingwith said outlet.
 3. A pump as defined in claim 1, including an annularfloat surrounding the portion of said pump body having the upper of saidinlets, surface liquid flowing over said float to said upper inlet.
 4. Apump as defined in claim 1, wherein said pump body is formed of twotelescoping parts, one of said inlets being formed in each of saidparts, the inner of said parts being movable into the outer of saidparts to close one of said inlets.
 5. A pump as defined in claim 1,wherein the upper of said impellers is spaced closer to said top wallthan the spacing between the lower impeller and said bottom wall.
 6. Apump as defined in claim 5, wherein the upper of said inlets is locatedabove said top wall, said upper inlet communicating with said chambervia said opening.
 7. A pump for liquids comprising: a. a pump bodyhaving an inlet and an outlet; b. first and second walls within saidbody defining an impeller chamber communicating with said inlet andoutlet, said inlet being in said first wall, c. an impeller shaftextending into said chamber through an opening in said second wall, d.means for rotating said shaft, and e. first and second independentimpellers within said chamber and fixed to and rotatable with saidshaft, said impellers being spaced apart along the length of said shaft,said first impeller being spaced relatively far from said first wall butsaid first impeller being closer to both said inlet and outlet than saidsecond impeller and serving to draw liquid through said inlet anddischarge liquid through said outlet, said impellers being arranged sothat most of the liquid moves through only said first impeller as itflows from said inlet to said outlet and said second impeller beingspaced relatively close to said second wall and urging liquid towardsaid outlet in a direction opposite to the direction in which said firstimpeller moves liquid, thereby preventing any liquid from moving throughsaid opening from said chamber, the space between said impellers beingfilled with liquid which serves to prevent air, entering said chamberthrough said opening, from reaching said outlet.